'Library of the Earth' at OSU May Hold Clues to Environmental Mysteries

October 29, 2009

CORVALLIS, Ore. - To the uninformed observer, the 14,000-plus meters of ocean sediment stored in PVC pipe and housed in a refrigerated warehouse on the edge of the Oregon State University campus looks like so much gray goo.

But within those core samples, taken from oceans all over the world during the past 35 years, may reside the keys to understanding oceanic "dead zones," the frequency of catastrophic earthquakes in the Pacific Northwest, historic triggers to rapid global climate change, and even the origins of life.

Scientific interest in the repository, which has been funded by the National Science Foundation, is exploding, according to Nicklas G. Pisias, a professor in OSU's College of Oceanic and Atmospheric Sciences, who directs the laboratory.

"It's one of our hidden tourist attractions on the OSU campus," said Pisias, with a laugh. "Every year, quite a number of researchers from around the country visit the lab to conduct research on the core samples. And we ship out many more samples to scientists around the world."

The coring program receives little publicity but is highly valued by scientists. The college has two full-time technicians who work with researchers from OSU, as well as from other universities and agencies, and supervise coring operations aboard ship during research cruises. The job is technical and presents a logistical headache. During a typical sampling cruise, OSU technicians Dale Hubbard and Chris Moser bring 100,000 pounds of gear to sea, shipped to port in a pair of containers about the size of a typical railroad freight car.

Cores, up to 25 meters in length, are usually cut in 1.5 meter sections and sent back to the OSU Core Lab, where they are cut in half, photographed and preserved. Most are stored on site because other universities lack adequate facilities and the technical know-how to preserve the samples, Pisias said.

What scientists discover in those samples continually surprises, enlightens and sometimes mystifies the scientific community.

"Two years ago, we were coring in the south Pacific and found a huge area that had absolutely no sediment," Pisias said. "The ocean floor there is very old, yet we couldn't find a centimeter of sediment. And no one knew such an area existed. There is something unusual going on there with ocean currents and undersea processes that needs to be explored."

This summer evidence was unveiled by OSU researchers Jane Lubchenco, Francis Chan and others outlining the worsening case of hypoxia off the Oregon coast. It is the fifth consecutive year that oxygen levels in waters off the central Oregon coast were sufficiently low to kill off marine life. Those waters did, in fact, contain some of the lowest oxygen levels directly observed by scientists and bordered on "anoxia," or complete oxygen deprivation.

But indirect evidence of past anoxia can be found in the OSU Core Lab, according to Pisias. Core samples from northern California show layers of lamination that are indicators of anoxia, where there has been no biological activity for a period of years, even decades.

"What's important to note is that those core samples weren't taken for the purpose of studying anoxia," he pointed out. "It was a completely different research project. It shows the value of retaining and archiving these core samples because they provide a unique history of Earth through a variety of different scientific lenses."

OSU marine geologist Chris Goldfinger uses the lab to study core samples from throughout the Pacific Ocean that contain coarse particles called "turbidites," which accumulate during earthquake events. By comparing age and distribution of these turbidites, he has been able to put together a timeline of major seismic events in the Pacific Northwest that suggests the region has had 23 major earthquakes during the past 10,000 years - and may be due for another in the magnitude 9.0 range.

"The lab is like a library of the Earth," Goldfinger said. "Some of the evidence for great earthquakes in Cascadia was collected in the late 1960s - at about the time plate tectonics was discovered. More than 20 years later, it was realized that the cores contained a record of these huge earthquakes."

There are more than 5,600 cores in the OSU lab. Each has been cut in half, with one half used for scientific study and the other for archival purposes. During the first year, only a project's principal investigator may work on the core sample. In year two, other scientists from that institution or project may have access. After that, it falls into scientific "public domain," Pisias said.

To make the cores last longer, small samples are cut off and shipped to research labs for more detailed analysis. During the past three years, OSU shipped out more than 45,000 samples to 96 investigators in 11 different countries. The research supported by the core lab is varied.

"Some of the work is seismic, while other studies look at the deep biosphere - including studies of bacteria that may provide clues about the origin of life - as well as climate change, and continental margins," Pisias said. "We also have a special section for Arctic research."

The oldest sediment samples date back 40 million years. Cores from other areas, like off the Columbia River, are much younger because the sediment piles up so quickly. To the uninformed observer, they look suspiciously alike.

Scientists like Pisias and others, however, can read the gray goo like a Grisham novel.

"There are core samples we have from the middle of the ocean, where it's a biological desert, but you can tell immediately where they're from because they contain tiny bits of red clay," Pisias said. "It's carried in by the wind and drops to the ocean floor. It's all you'll find there."

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